1. Field of the Invention
The invention relates to a security gate which can be positioned and removed with one hand.
2. Description of Related Art
There are numerous security gates on the market and known in the prior art. However, almost all share problems in the general areas of ease of use, human factors, and/or ease of installation and removal.
One of the most difficult aspects of prior art security gates is that more than one hand is usually required to install or remove the gate. Only a few security gates are operable with one hand, however, their mechanisms and structures are very different from the present invention. See, for example, U.S. Pat. No. 2,581,857. In contrast, according to the gate of the present invention, a handle located at the top of the gate is used both to carry the gate and to operate the release mechanism, thereby allowing true one-handed operation. French Pat. No. 992,830 describes a door and window locking mechanism in which a single handle causes a pair of spring-loaded bolts to withdraw from or contact the door or window frame. The mechanism otherwise described in French Pat. No. 992,830 appears to be irrelevant in the context of a security gate.
With most prior art gates the main adjustment is lost every time the gate is removed. Therefore the gate must be painstakingly readjusted every time it is used, leading to a greater likelihood of improper installation. With some other gates, the adjustment is held when the gate is removed. However, changing doorways means carefully readjusting the gate for each doorway. In contrast, with the gate of the present invention, the coarse adjustment is made easily and can be remembered, either by mentally noting the indicator position or the user may mark the indicator position with a suitable writing instrument. Once the present invention is adjusted for a given doorway, no further adjustment is needed to repeat installing and removing the gate from the same doorway.
Many security gates make no provision to adequately prevent a child from operating the mechanism which releases the gate. In other cases, the only obstacle to a child's removing the prior art gate is that high force is required to operate the mechanism. However, the high force prior art approach has clear disadvantages to the user, especially when the gate is installed or removed by an adult with below average strength as may be the case with an elderly individual. In contrast, the present invention provides two interlocks which prevent a child from releasing the gate. The two interlocks employed by the present invention require two distinct, separate operations that are generally difficult for a child to coordinate.
With regard to many prior art security gates, the loading of the gate in the doorway, and therefore its security in the doorway, is very sensitive to the specific manner in which the gate is adjusted during installation. The installation adjustment is often left to the judgment of the user with very little guidance. Small changes in adjustment to such prior art gates produce large changes in loading. As a consequence, it is quite easy for the user to install a prior art gate either too loose, so that it is not secure, or too tight, which risks damaging either the gate itself or the doorway, wall, or whatever it is installed in. For example, some gates require pushing a lever into a given notch. Missing the correct prior art notch by one notch in one direction makes the gate too tight and missing the prior art notch by one in the other direction leaves the gate too loose. Additionally, it is often difficult to determine the correct notch in the first place with many prior art gates, thereby requiring a fussy trial-and-error procedure. This problem is overcome by the device of the present invention by incorporating a compressed spring which has a relatively low spring rate. This unique feature permits additional changes in the compression of the spring to require a small relative increase in the total overall force applied to the plungers. The result is that the present invention is much easier to adjust for a given doorway.
In addition to the prior art described in detail above, the following U.S. patent may also be relevant to the general state of the art: U.S. Pat. Nos. 903,564; 2,559,066; 2,756,469; 2,851,746; 2,896,277; 2,928,146; 3,000,063; 3,163,205; 3,216,482; 3,885,616; 4,465,262; 4,492,263 and 4,607,455.